This invention is generally directed to developer compositions, and more specifically, the present invention relates to developer compositions with coated carrier components, or coated carrier particles that can be prepared by, for example, solution and preferably by dry powder processes. More specifically, the present invention relates to compositions, especially carrier compositions comprised of a core, and thereover a polymer, or polymers with amine, such as a number of the amines of the above copending applications and patents, and a second polymer containing a carboxylic acid functionality, or a sulfonic acid functionality.
In embodiments of the present invention, the carrier particles are comprised of a core with a coating thereover of a polymer or polymers generated from a mixture, or blend of an amine, such as dimethylaminoethyl methacrylate, substituted alkyl aminoethyl methacrylate, butylaminoethyl methacrylate, and the like, and a second polymer containing a carboxylic acid functionality, or a sulfonic acid functionality. The carrier may include the polymer coating thereover in admixture with other suitable polymers, and more specifically, with a polymer, such as a fluoropolymer, polymethylmethacrylate, poly(urethane), especially a crosslinked polyurethane, such as a poly(urethane) polyester and the like, and moreover, the copolymer coating may contain a conductive component, such as carbon black, and which conductive component is preferably dispersed in the polymer coating. With the conductive component, there can be enabled carriers with increased developer triboelectric response at relative humidities of from about 20 to about 90 percent, improved image quality performance, excellent high conductivity ranges of from about 10.sup.-10 to about 10.sup.-7 (ohm-cm).sup.-1, and the like. An important advantage associated with the carriers of the present invention with a second polymer containing a carboxylic acid functionality, or a sulfonic acid functionality polymer thereover include the enablement of a crosslinked polymer, which crosslinking permits, for example, robust, extended life carriers with lifetimes, for example, of 1,000,000 imaging cycles, a high triboelectrical charge, for example a carrier tribo range of from about a plus (positive charge) 30 to about 100 microcoulombs per gram, and preferably from about a positive 40 to about a positive 70 microcoulombs per gram, and most preferably from about a positive 35 to about a positive 60 microcoulombs per gram. The carrier particles of the present invention can be selected for a number of different imaging systems and devices, such as xerographic copiers and printers, inclusive of high speed color xerographic systems, printers, digital systems, such as the Xerox Corporation Document Center 240/265, 5090, DocuTech Production Publisher, Model 135, 5775, 5100, a combination of xerographic and digital systems, and wherein colored images with excellent and substantially no background deposits are achievable.
Developer compositions comprised of the carrier particles illustrated herein and prepared, for example, by a dry coating process are generally useful in electrostatographic or electrophotographic imaging systems, especially xerographic imaging and printing processes, and digital processes. Additionally, the invention developer compositions comprised of substantially conductive carrier particles are useful in imaging methods wherein relatively constant conductivity parameters are desired. Furthermore, in the aforementioned imaging processes the triboelectric charge on the carrier particles can be preselected, which charge is dependent, for example, on the polymer composition and dispersant component applied to the carrier core, and optionally the type and amount of the conductive component selected.